活動內容
It is well known that the magnitude of band offset (BO) at any semiconductor heterojunction results entirely from the distribution of charge at that interface, and that the latter is a result of minimization of interface energy. Existing BO theories, however, make little use of the energy minimization requirement, likely because the equilibrium charge densities at heterojunction interfaces seem difficult to predict. In this work, electron densities at a large number of (100), (110), and (111) oriented heterojunctions between lattice-matched, isovalent, semiconductors with the zinc blende (ZB) structure have been calculated by first principles methods and analyzed in detail for possible common characteristics of energy-minimized densities. Strikingly, heterojunction electron density was found to largely depend only on the immediate, local atomic arrangement: so much so that a juxtaposition of local electron-densities generated in oligo-cells (LEGOs) accurately reproduced the charge den